U.S. patent number 6,477,455 [Application Number 09/891,076] was granted by the patent office on 2002-11-05 for device to control the dynamic stability of an industrial vehicle.
This patent grant is currently assigned to Dana Italia S.p.A.. Invention is credited to Fabrizio Panizzolo.
United States Patent |
6,477,455 |
Panizzolo |
November 5, 2002 |
Device to control the dynamic stability of an industrial
vehicle
Abstract
A device to control the dynamic stability of an industrial
vehicle, where the chassis of the aforesaid vehicle is fitted with
a pair of axles (10', 10"), extending from each of which are booms
(12, 13, 12', 13'), fitted to the ends of which are articulated
steering pivots (14, 15, 14'15') of the wheels of the aforesaid
vehicle and where interposed between the axle (11) and the frame
(16) of the aforesaid industrial vehicle are hydraulic cylinders
(17, 17', 18, 18'), said control device providing that each
hydraulic cylinder (17, 17', 18, 18') is associated with pressure
transducers capable of indicating the loads weighing
instantaneously on each wheel hub, thus permitting, by means of
appropriate data processing, detection of the condition of
stability of the vehicle, said pressure transducers (31-34) being
associated with hydraulic cylinders (17, 17', 18, 18') so as to
operate in real time to provide the initial data to process the
conditions of stability on which to base the control of vehicle
stability.
Inventors: |
Panizzolo; Fabrizio (Padova,
IT) |
Assignee: |
Dana Italia S.p.A. (Arco,
IT)
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Family
ID: |
11445371 |
Appl.
No.: |
09/891,076 |
Filed: |
June 25, 2001 |
Foreign Application Priority Data
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Jun 28, 2000 [IT] |
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MI00A1463 |
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Current U.S.
Class: |
701/37;
280/124.161; 280/5.508; 701/32.8; 701/34.2; 701/34.4; 701/39 |
Current CPC
Class: |
B60G
9/02 (20130101); B60G 17/015 (20130101); B62D
49/08 (20130101); B66C 23/905 (20130101); B66F
9/07586 (20130101); B66F 17/003 (20130101); E02F
9/2257 (20130101); E02F 9/24 (20130101); B60G
2200/32 (20130101); B60G 2400/51 (20130101) |
Current International
Class: |
B60G
17/015 (20060101); B60G 9/00 (20060101); B60G
9/02 (20060101); B62D 49/08 (20060101); B62D
49/00 (20060101); B66C 23/90 (20060101); B66F
17/00 (20060101); B66F 9/075 (20060101); B66C
23/00 (20060101); E02F 9/22 (20060101); E02F
9/24 (20060101); B60G 021/073 () |
Field of
Search: |
;701/37,50,29,31,35,38,39 ;702/34 ;296/181,190 ;180/89.12
;280/6.154,124.161,840 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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3711239 |
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Oct 1987 |
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DE |
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0 675 069 |
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Oct 1995 |
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EP |
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11091622 |
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Sep 1997 |
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JP |
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Other References
Primary Examiner: Cuchlinski, Jr.; William A.
Assistant Examiner: To; Tuan C
Attorney, Agent or Firm: Hedman & Costigan, P.C.
Claims
What is claimed is:
1. A device to control the dynamic stability of an industrial
vehicle having wheels nd a wheel hubs where the chassis (16) of
said vehicle is fitted with at least one pair of axles (10', 10"),
extending from each of which are booms (12, 13, 12', 13') fitted to
the ends of which are articulated steering pivots (14, 15, 14',
15') on which are mounted wheels of said industrial vehicle, and
where interposed between an axle (11) and the chassis (16) of said
industrial vehicle are hydraulic cylinders (17, 17', 18, 18'),
wherein each of said hydraulic cylinders (17, 17', 18, 18'), are
associated with pressure transducers (31-34) capable of
instantaneously indicating the weight on each of said wheel hubs, a
control unit (39) having an input means connected to said
transducers 31-34, and data processing means for recognition of the
condition of stability of said vehicle.
2. Device (30), as claimed in claim 1, characterised in that each
of the aforesaid pressure transducers (31-34) is associated with at
least one of the aforesaid hydraulic cylinders (17, 17', 18, 18'),
so that each of the aforesaid pressure transducers (31-34)
transmits its signal to the aforesaid control unit (39), which
processes a signal relevant to the condition of stability of the
vehicle, said cylinders being operated by said pipes (42-45).
3. Device (30), as claimed in claim 1 or 2, wherein said control
unit (39) sends signals processed by it to an appropriate
logic-hydraulic system incorporating appropriate hydraulic valves
to control the flow of hydraulic fluid towards the pipes (42-45),
each of which is associated with one of said hydraulic cylinders
(17, 17', 18, 18') so as to act dynamically on the stability of
said vehicle.
4. Device (30), as claimed in claim 2, wherein said control unit
(39) receives from a block (40), data relevant to the particular
vehicle to which the device (30) is fitted and processes a signal
relevant to the condition of stability of the vehicle, also taking
account of data acquired by said control unit (39), that is stored
by the device (30) beginning when said vehicle is manufactured.
5. Device (30), as claimed in claim 4, wherein said block (40)
operates by means of acquiring data from said transducers (31-34),
and storing said data in said control unit (39) for incorporation
into a self-learning system for stabilizing said vehicle.
6. Device (30), as claimed in claim 1, characterised in that the
pressure inside the aforesaid hydraulic cylinders (17, 17', 18,
18') can be regulated by means of an appropriate logic-hydraulic
circuit incorporating appropriate valves to control the flow.
7. Device (30), as claimed in claim 1, characterised in that each
of the aforesaid pressure transducers (31, 32, 33, 34) is
associated with a respective amplifier (35, 36, 37, 38) to send the
aforesaid amplified signals to the aforesaid control unit (39).
8. Device (30), as claimed in claim 1, characterised in that it is
capable of recognising variables such as the extension of the boom
of the crane and any downward inclination of the forks fitted to
the end of said boom that supports the actual load.
9. Device (30), as claimed in claim 1, characterised in that it is
capable of recognising the limit condition of lateral stability, in
the case of which it emits a signal that disables vehicle starting,
acting on the transmission to thus prevent motion of the
vehicle.
10. Device (30), as claimed in claim 1, characterised in that it is
provided with an acoustic and/or visual warning device which warns
the vehicle operator of the possibility of limit conditions of
vehicle stability.
11. Device (30), as claimed in claim 1, characterised in that it is
provided with a longitudinal self-levelling mode in conditions of
full load when travelling at low speeds with the shock absorbing
system of the suspensions deactivated.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a device to control the dynamic
stability of an industrial vehicle. More specifically, the device
according to the present invention is appropriate to be fitted on
an industrial vehicle such as lift trucks with telescoping boom,
bucket loaders or back-hoe loaders, crane trucks, tractors and
similar.
As is known, during operations to manoeuvre or work with these
industrial vehicles, the casing or chassis of the vehicle is
subjected to a plurality of external loads which can be schematised
as forces and moments of forces that tend to influence the
stability of the vehicle.
This is accentuated by these phenomena occurring with the vehicle
fully loaded and/or on uneven ground. In fact, during operations to
manoeuvre an industrial vehicle with suspensions, the entire casing
or chassis of the vehicle is subjected to various stresses
determined by a series of forces and overturning moments that are
produced both due to movement of the load or due to variations in
the stability of the vehicle in motion on the ground, all of which
may occur in static, almost-static or dynamic conditions.
Measurement of external physical sizes is useful to determine the
conditions of operation and stability of the vehicle; for example,
it is possible to measure the vertical forces and overturning
moments in the various directions of the space to calculate the
stability of industrial vehicles with axles with suspensions,
during the various manoeuvres of turning, braking, acceleration or
lifting the load, in order to calculate the induced forces and the
moments of destabilisation of the vehicle.
Currently, the operation to measure these forces and moments can be
performed using specifically designed measurement instruments, only
by simulation to be performed in the laboratory.
Moreover, to date, the various physical sizes of interest are
measured approximately and placed in relation to one another by
means of force transducers, which are fixed only externally to the
casing of the axle or the chassis of the vehicle, thus influenced
by all possible effects of disturbance or drift of the signal to be
measured, which can be influenced by the effects of temperature,
deflections of the structural components of the axle, operating
pressures of the brakes, making the final information inaccurate
and unreliable.
Therefore, fitting these transducers in specific positions of each
rotating axle does not permit accurate measurements, as they are
influenced by many external factors, in addition to those intrinsic
to the geometry of the axle or the coupling of the axle with the
vehicle chassis.
Lastly, all this requires the development of complex transformation
algorithms, appropriate to translate the position through time of
each vehicle axle into the fixed coordinates system of the
vehicle.
SUMMARY OF THE INVENTION
The object of the present invention is, therefore, to produce a
device for controlling the dynamic stability of an industrial
vehicle which operates in an active and integrated mode in the
vehicle, during its normal use, to guarantee the best conditions of
stability and self-levelling of this vehicle.
Another object of the present invention is to produce a device for
control of the dynamic stability of an industrial vehicle, which
can be installed simply and which may allow an operator sitting in
the cab to be informed of all conditions in the vicinity of the
limit of stability in which the vehicle finds itself operating.
Yet another object of the present invention is to present a device
for control of the dynamic stability of an industrial vehicle which
considerably increases the reliability and overall comfort of the
vehicle to which it is fitted, reducing stresses to which the
chassis of the vehicle might be subjected.
These and other objects are attained by a device that controls the
dynamic stability of an industrial vehicle, where the chassis of
said vehicle is fitted with at least one pair of axles (10', 10"),
extending from each of which are booms (12, 13, 12', 13') fitted to
the ends of which are articulated steering pivots (14, 15, 14',
15') of the wheels of said vehicle, and where interposed between
the axle (11) and the chassis (16) of said industrial vehicle are
hydraulic cylinders (17, 17', 18, 18'), wherein each of said
hydraulic cylinders (17, 17', 18, 18'), is associated with pressure
transducers (31-34) capable of indicating the loads weighing
instantaneously on each wheel hub, using said weight information
from said pressure transducers (31-34) in data processing,
recognition of the condition of stability of said vehicle, said
pressure transducers (31-34) being associated with said hydraulic
cylinders (17, 17', 18, 18') so as to detect and provide the
control unit, as said information is received, (39) with input data
on which to base assessment of the stability of said vehicle.
Further characteristics of the present invention are also defined
in the subsequent claims.
BRIEF DESCRIPTION OF THE DRAWINGS
Further objects and advantages of the present invention shall
become clearer from the description below and the annexed drawings,
provided merely as an exemplary and non-limiting example, in
which:
FIG. 1 shows a front view of a pair of axles, fitted on a generic
chassis of an industrial vehicle, incorporating the device for
control of the dynamic stability, according to the present
invention, said axles being positioned mutually in a first
operating position;
FIG. 2 shows a front view of the pair of axles in FIG. 1, in a
second mutual operating position;
FIG. 3 shows a view, in a part section according to a plan
perpendicular to the axis of one of the axles, of an assembly
comprising part of the axle and a hydraulic cylinder, which sends
pressure to a transducer positioned therein to electronically read
the pressure measurement (on each wheel hub respectively) in order
to process data required to establish conditions of dynamic
stability of an industrial vehicle, according to the present
invention; and
FIG. 4 shows a block diagram showing the operating logic of the
device for control of the dynamic stability of an industrial
vehicle, according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
With specific reference firstly to FIG. 1-2, the axle assembly is
indicated globally with the numeric reference 10, and in FIGS. 1-2
it can be seen that each axle 10', 10" comprises a central casing
11 from which booms 12 and 13 and 12' and 13' extend.
At the end of each of the booms 12, 13, 12' and 13' are articulated
steering pivots 14, 15, 14', 15' of the wheels; said wheels are not
shown for simplicity. The central casing 11 also supports a
steering actuator, capable of making its rod slide axially.
Moreover, interposed between the axle 11 and the chassis 16 of the
industrial vehicle are hydraulic cylinders 17, 17' and 18, 18'.
The hydraulic cylinders 17, 17' and 18, 18'are connected to hinges
19, 20 integral with the chassis 16.
The rods of the hydraulic cylinders 17, 17' and 18, 18' are instead
connected to hinges 21, 22, 21' and 22' integral with the booms 12
and 13 and 12' and 13' of the axles 11.
The hydraulic cylinders 17, 17' and 18, 18' are fed by an
electronically controlled hydraulic control unit. No further
detailed description of the structure of the pair of axles and
their assembly on the chassis of an industrial vehicle is given
herein and, therefore, only the functional elements useful to
interpret and actuate the invention are referred to.
Each of the hydraulic cylinders 17, 17' and 18, 18' is controlled
by the device for control of the dynamic stability of an industrial
vehicle, according to the present invention, the block diagram of
which is shown globally with the numeric reference 30 in FIG. 4.
The device 30 is firstly provided with pressure transducers 31, 32,
33 and 34, each of which is associated with a respective hydraulic
cylinder 17, 17' and 18, 18'.
Each of the pressure transducers 31, 32, 33 and 34 transmits a
signal to a respective amplifier 35, 36, 37 and 38 and these
amplified signals are sent to a control unit 39.
The control unit 39 also receives, from a block 40, data relevant
to the specific vehicle to which the device 30 is applied; in fact,
the block 40 can memorize or receive data such as type of vehicle,
weight, significant dimensions such as track, wheel base, length
and significant angles of any lifting booms of crane trucks and/or
similar vehicles, etc., all through an intelligent self-learning
system which activates itself after installation of the device for
stability of the vehicle coming off the assembly line. Taking
account of the information received from the pressure transducers
31, 32, 33 and 34 together with the information received from the
block 40, the control unit 39 processes a signal relevant to the
condition of stability of the vehicle, all in real time.
This signal of the control unit 39 is further processed by a block
41 which transmits it to an appropriate logic-hydraulic system
incorporating appropriate hydraulic valves to control the flow
towards a plurality of actuation pipes 42, 43, 44 and 45, each of
which is associated with one of the hydraulic cylinders 17, 17' and
18, 18'.
Essentially, the electronic circuit schematised in FIG. 4, by means
of appropriate control software, processes data received from each
pressure sensor 31, 32, 33, and 34, appropriately amplified, so as
to calculate the stability of the vehicle in real time and take
appropriate measures to dynamically balance the aforesaid vehicle,
acting through the actuation pipes 42, 43, 44 and 45 independently
on the hydraulic cylinders 17, 17' and 18, 18'.
More specifically, the pressure and oil volume inside each
hydraulic cylinder 17, 17' and 18, 18' can be regulated by means of
an appropriate logic-hydraulic system incorporating appropriate
hydraulic valves to control flow.
In the case of industrial vehicles such as lift trucks with
telescoping boom or industrial cranes, the device 30 also takes
account of other important variables such as the extension of the
boom of the crane and any downward inclination of the forks fitted
to the end of this boom, as the load to be lifted is applied to the
aforesaid ends and/or forks.
The system recognises the overturning moment, as a consequence
recognising the decrease in the load on the axles, in particular on
the rear axle, after having appropriately processed the data
supplied for the purpose of stability.
If the industrial vehicle is not working on flat ground, the device
according to the invention is capable of recognising the limit
condition of lateral stability: the signal transmitted by the
software could therefore disable vehicle starting, acting on the
transmission to prevent motion.
It is also possible to associate the device 30 with an acoustic
and/or visual warning device which indicates the possibility of
limit condition of vehicle stability to the vehicle operator.
The characteristics of the device for control of the dynamic
stability of an industrial vehicle, to which the present invention
relates, become more apparent from the description above, as do the
advantages. To pinpoint these advantages better the following
considerations are set down.
The presence of the device described allows high reliability of the
vehicle, simultaneously increasing the comfort of use.
Moreover, vehicles equipped with the device according to the
invention are safer and easier to drive than those not fitted with
the device.
This allows greater driving comfort and an overall decrease in
stress and fatigue for the operator of the industrial vehicle, thus
increasing productivity.
The device allows the vehicle to which it is fitted to be
transformed into a dynamic system permitting prevention of
dangerous limit conditions that would lead to instability of the
vehicle.
It is clear that the device can be fitted to any type of axle with
suspension, for example, also to axles without a Panhard rod, that
is with different suspension geometries than those indicated
herein.
The system of the invention thus allows active control to be
obtained, especially with self-stabilisation of the vehicle, which
is extremely interesting when moving at relatively high speeds off
road, especially with a load at a considerable height from the
ground.
It is also possible to actuate a longitudinal self-levelling mode
of the vehicle in conditions of full load when travelling at low
speeds.
In this case, the shock absorbing effect of the suspensions is
deactivated, the axle thus acting as if it was connected rigidly to
a component of the articulated quadrilateral identified between the
chassis of the vehicle, the suspension cylinders, the axle and the
Panhard rod, as in annexed FIG. 3.
Lastly, it is apparent that numerous other variants may be made to
the device for control of the dynamic stability of an industrial
vehicle, to which this invention relates, without departing from
the principles of intrinsic novelty of the invention.
In the practical actuation of the invention, the materials, forms
and dimensions of the details illustrated may vary according to
requirements and these may be substituted with others of technical
equivalence.
* * * * *